Butter contains trace amount of lactose making it easy to consume by lactose intolerant people. One cup of butter contains about 0.1 grams of lactose and people who are intolerant to lactose can consume about 12 grams of lactose at one time without the occurrence of symptoms. So butter mostly is safe to consume by lactose intolerant people. In very rare cases, people who are highly sensitive will experience symptoms of lactose intolerance.